In construction, it is frequently desirable to support a portion of a building under construction or under renovation. For this purpose temporary support columns are used. A wide variety of such columns have been proposed in the past. However most of such columns have been designed for the purpose of merely holding a floor or roof in position while other work is done. Simple columns are available which have threaded extensions. These columns are extendable only to a limited extent. The purpose, in such columns is usually to facilitate the erection of the columns, and to be extended to support a structure, and not to actually raise part of the building.
In certain cases particularly renovation or alteration of a building, it is desirable to not only support a structure with plurality of such columns, but also to raise, or lower such a portion of a building which is supported on such columns.
In this case, where the elevation of the supported building portion is to be changed, it is essential that the supported portion of the building shall be maintained level, or at its predetermined orientation. For example, if it is desired to renovate or alter a building by for example elevating the entire roof of the building or a portion of the roof of the building to a new elevation, then clearly the entire roof that is to be moved must be supported and raised or lowered to a new position. The entire portion of the building that is to be moved must be moved without changing its plane or shape. The supporting structure used for this purpose must be capable of carrying that load and holding it in a new position for as long it takes to complete the other alterations or renovations of the building.
In the past, this has generally speaking being achieved in a some what unsatisfactory manner.